This invention relates to a process for making esters and, more particularly, to methyl 4-oxobutyrate and its methanol addition products, viz., methyl 4,4-dimethoxybutyrate and gamma-methoxy-gamma-butyrolactone, from the catalyzed reaction of acrolein, carbon monoxide and methanol. Methyl 4-oxobutyrate is a useful intermediate in the production of a variety of industrially useful compounds including gamma-butyrolactone, 1,4-butanediol and glutamic acid.
U.S. Pat. No. 3,382,274 to Fenton describes the reaction of an aliphatic, alpha, beta-ethylenically unsaturated aldehyde such as acrolein with an aliphatic or alicyclic primary alcohol such as methanol in the presence of mercuric ion to yield an ester of a beta-alkoxy aliphatic carboxylic acid. U.S. Pat. No. 3,397,225 to Fenton, et al. describes the oxidative carbonylation of an olefin, carbon monoxide and alkanol in the presence of a platinum group metal and a soluble salt of a multi-valent metal as an oxidant having an oxidation potential more positive than the platinum group metal to provide the ester of an alpha, beta-unsaturated carboxylic acid having one more carbon than the starting olefin. In a somewhat similar process, that of U.S. Pat. No. 3,437,676 to von Kutepow, et al., a carbonylation reaction is carried out in which olefin, carbon monoxide and alcohol are reacted in the presence of a catalyst such as palladium dichloride bis(triphenylphosphine) to provide a carboxylic acid ester. U.S. Pat. No. 4,245,115 to Butter describes a similar carbonylation employing, as catalyst, a palladium salt complexed with an arsine or stibine ligand, e.g., palladium dichloride bis (triphenylarsine) or palladium dichloride bis (tri-p-tolylarsine). The process of U.S. Pat. No. 3,980,697 to El-Chahawi, et al. provides beta-alkoxy-butyric acid alkyl esters by the reaction of allyl halides with carbon monoxide, alkali alcoholates and alcohols. U.S. Pat. No. 2,040,944 to Lazier and U.S. Pat. No. 2,091,800 to Adkins, et al. show that the reaction of an ester with hydrogen provides an alcohol. U.S. Pat. No. 3,065,243 to Dunlop, et al. describes the preparation of gamma-butyrolactone by the hydrogenation of the anhydrides or esters of succinic acid or maleic acid. Similarly, U.S. Pat. No. 3,113,138 to Franko-Filipasic, et al., U.S. Pat. No. 3,214,385 to Kolyer, U.S. Pat. No. 3,580,930 to Miya, et al. and U.S. Pat. No. 4,048,196 to Broecker, et al. each describes the preparation of gamma-butyrolactone by the hydrogenation of succinic anhydride.